Automatic ice maker



Aug. 2, 1960 H. E. ROEDTER 2,947,156

AUTOMATIC ICE. MAKER Filed May 2. 1957 4 Sheets-Sheet l J g 1 INVEN TOR.

HENRY E. ROEDTER.

BY r

ATTORNEYS.

Aug. 2, 1960 H. E. ROEDTER 2,947,156

AUTOMATIC ICE MAKER Filed May 2. 1957 4 Sheets-Sheet 2 INVENTOR.

HENRY E. ROEDTER.

ATTORNEYS.

Aug. 2, 1960 H. E. ROEDTER AUTOMATIC ICE MAKER 4 Sheets-Sheet 3 Filed May 2, 1957 INVENTOR.

HENRY E. ROEDTER.

ATTORNEYS.

Aug. 2, 1960 H. E. ROEDTER AUTOMATIC zcs MAKER Filed ma 2, 1957 4 Sheets-Sheet 4 INVENTOR.

HENRY E. ROEDTER.

wil

ATTORNEYS.

Paientednag. a, teen AUTOMATIC rcr. MAKER Henry Edward Roedter, Hamilton, Ohio (538 Clinton Springs Ave;, Cincinnati 17, ()liio) FiledMay 2, "1957, Ser. No. 656,548

' Claims; c1. s2--3'5s The present invention relates broadly to a mechanism for making ice, and concerns more specifically an automatic ice maker adapted for installation and use in a domestic refrigerator or home freezer.

The present invention relates to that class of equipment which includes a mold for freezing liquid, such as water, which, afte'r'beihg frozen solid,is harvested or ejected from the mold which is subsequently filled with fresh liquid in preparation for another harvesting cycle. Ejection of solids, and filling of the mold with liquid, are automatically controlled in the presentinvention by an electrical system.

Briefly stated, the present invention comprises a mold which is secured to one wall of a cooled surface, such as an evaporator; Themold defines a plurality of cavities with which are associated concentric pistons forming the bottoms of'the cavities. Water supplied to the cavities eventually freeies solid because of heat transfer through the mold to the cooled surface. After the ice has frozen, a thermostat makes electrical contact and energizes a pumping system which forces fluid under pressure against the pistons, thereby displacing them into the mold cavities and ejecting the ice. Guides are provided adjacent the mold cavities to direct the ice into a receptacle where it accumulates until a pivoted detector arm, associated with the automatic control system, detects that the receptacle is substantially full, at which time operation of the ice maker is terminated; The mechanism will resume operation as soon as the detector arm senses that icehas been removed. fromthe receptacle.

After'the masses of ice are ejected, the pistons are retracted to their original positions and fresh water is supplied to the cavities under the control of an electric timer.

In view of the foregoing, it will be appreciated that a. fundamental object of the present invention is to provide an improved automatic ice maker, particularly one which is well adapted for use in domestic refrigeration units.

A somewhat more specific object of the invention is the provision of automatically controlledrneans for producing discrete masses of icerwhich are stored within'a refrigerated unit, the means being energized automati-- quire application of heat to free the ice from the molds:

In'this connection, it is also an advantage of theinv'ention that-the ice when=- ejected from the molds 'has' a dry surface so that subsequent air'dryi'ng is not "required,

Anotherspecifieobject of the invention is toprovide a pair of concentric pistons; the larger-diameter one of which develops a great force during actuation of a fluid a pressure system fo'r'breaking ice loose from an associated mold cavity, the smaller-diameter one developing a lesser force for physically ejecting the ice.

A still further object comprises provision of concentric pistons, the outer one of which executes a relatively small stroke for breaking ice loose from an associated mold cavity while the inner one executes substantially greater travel for ejecting the ice from the cavity.

The novel features that I consider characteristic of my invention are set forth in the appended claims; the

invention, itself, however, both as to its organization and advantages'thereof, will best be understood from the following description of a specific embodimentwhen read in conjunction with the accompanying drawings, in which:

Figure 1 is afront elevational view of a domestic re frigerator showing my novel ice maker installed within the evaporator;

Figure 2 is a perspective View of a section of the evap orator showing the mold assembly attached thereto;

Figure 3 is a cross-sectional view through a mold cavity taken on plane 3--3 of Figure 2, showing the pistons in retracted position;

Figure 4 is a cross-sectional view taken on the same.

plane as Figure 3 but showing the pistons associated with the mold cavity in anrextended position for ejecting ice from the cavity;

Figure 5 is 'a fragmentary sectional view taken on plane 5-5 of Figure 3, showing a stationary stop pin vention finds utility in a domestic refrigerator, generally indicated by the reference numeral 1, although it should be understood that the invention may also be used in a home f'reezer or any other type of refrigerated unit in which below-freezing temperatures are attained. As il lustrated in Figure 1-, the refrigerator includes an access" door 2 and a horizontal evaporator 3 having a separate horizontally hinged door 4 secured nearits lower edge.

The mold assembly of the automatic ice maker is secured at the left of the evaporator, as generally indicated u at 5; It will be noted that the ice maker is positioned above a receptacle or tray 6 which receives the discrete ice masses 7 as they are ejected from the ice maker. A detector arm 8 is provided on theice maker for detect=" ing that the receptacle 6 is'filled with ice at which time the detector arm suspends operation of the ice maker,

such operation not being' a'gain' resumed until ice'is with drawn from the receptacle.

Attention is now directed to Figure 2 which shows the mold assembly 5 secured to the left Wall 9 of the evaporator 35 The assembly includes a mold 10 defin ing a plurality of cavities, generally designated 11, which ice is frozen through 'heat' transfer through the mold 10 to wall 9 of the evaporator. 'An ice guide 12- is positioned above the mold to deflect ic'e, ejected from the moldcavities, as will be explained, into the receptacle' 6.

The fact that the water has -frozen is detected by a thermostat 14 provided adjacent a mold cavity;

Structural details of the mold assembly The structural details of the mold assembly rn'aybest be understood from a study of Figures 2 through 5.

First, with reference to Figure 2, it will be noted that each mold cavity 11 has associated with it a piston assembly, generally designated 15. As illustrated in Figures 3 and 4, the piston assemblies serve as the bottom surfaces'16 of the mold cavities. greater detail later, the piston assemblies are extensible for ejecting the icemasses, but when retracted to the position-illustrated in Figure 3, aid in defining the mold cavities, which have theshape of truncated cones. The conical side walls of the cavities provide sufficient draft to assure that the ice masses can be broken freefrom the cavities and will not be locked therein. The shape of the ice masses imparted ,by the cavities is pleasing and makes them well adapted for domestic use, for example, in chilling beverages.

Directing attention panticularly'to Figure .3, it willbe noted that each piston assembly comprises an outer piston 17 and an inner concentric piston 18. Piston 17 has an inwardly extending concentric flange 19 which is formed with a central circular aperture through which piston 18 projects. Flange 19 normally engages anoutwardly extending flange 20 integrally formed on piston 18. Disposed between the pistons is a stationary cylindrical sleeve 21. The sleeve is formed with an inwardly extending annular flange 22'defining a central aperture which slidably engages piston 18. Thusthe sleeve and the outer piston provide spaced bearing surfaces for guiding the linear axial movement of piston 18.

Sleeve 21 defines a cylindrical cavity 23 within which is disposed a compression coil spring 24 which bears at its lower end against flange 20 and at its upper end against flange 22. The compressive force of this spring tends to retract piston 18 within the piston assembly at all times.

Attention should now be directed to stop pin 25 which is threadedly engaged with the mold 10 at 26. The stop pin is formed with a flange 27 which limits its penetration into piston assembly. From a close inspection of Figure 3, it will be noted that the reduced extended portion of the stop pin tightly engages sleeve 21 at 28 and holds it stationary. In contrast, the stop pin passes freely through a vertically elongated slot. 29 formed in one side wall of piston 17. This is illustrated in detail in Figure 5. A consideration of Figures 3 and will make,

it clear that piston 17 is limited in its vertical movements by the extent of the elongated slot 29. The purpose of providing this slot will be discussed more fully later in the specification.

Attention may now be turned to a plurality of seal rings which mutually seal the pistons 17 and 18 with respect to the sleeve 21 and mold proper, thereby making it possible for the piston assembly to serve as the watertight bottom of the mold cavity, Theseseal rings may take the form of rubber rings, or 0 rings as they are conventionally identified. Outer ring 31, which seats against the mold, is fitted Within annular groove 32 of piston 17 whereas inner ring 33 and intermediate ring 34 are fitted within annular grooves 35 and 36, respectively, of the sleeve. Ring 33 makes sealing engagement between piston 18 and flange 22 while ring 34 makes sealing engagement betweensleeve 21 andthe interior surface of piston 17. Through provision of these seal rings the outer and inner pistons may execute vertical movements without leakage of water or actuating fluid past their sealing'surfaces. V V

It will be noted that the lower end of piston 18 extends with clearance down into a cylindrical passage 37 to which fluid under pressure may be introduced through port 38. By virtue of the clearance between piston 18 and passage 37 fluid may flow to the lower ends of both pistons 17 and 1s. 7

As will be described more fully, water may be supplied to the mold-cavity where it will freeze to a solid mass. During the time period required for freezing, the piston assembly reposes in the'position shown in Figure 3. At the end of the freezing period, the pistons 17' and 18 may As will be explained in,

4 be vertically extended to eject the ice mass, as will now be described in connection with Figure 4.

When ice is to be ejected from the mold cavity, fluid is supplied to passage 37 by way of port 38 (Figure 3).

The fluid, which is under substantial pressure, acts on the lower ends of both pistons 17 and 18. Since a relatively large surface is presented by piston 17 against which the fluid may act, very substantial forces are generated for breaking the ice loose from its cavity. When this phase of operation is occurring, pistons 17 and 18 are elevated simultaneously by an amount equal to the elongation of slot 29 in excess of the diameter of stop pin 25. The extent of vertical movement of piston 17 is indicated at 39 (Figure 4). During this movement, flange 19 of piston 17 engages flange 20 of piston 18 and assures conjoint movement of the pistons. Thereafter, however, piston 17 can move no further because of the engagement of the bottom of slot 29 with the stop pin. The forces acting on the lower end of piston 18 continue to impart vertical movement to it thereafter until it is extended well into and above the mold cavity, as indicated at 40 in Figure 4; This movement of the inner piston forcibly and completely ejects the ice from the cavity. During the latterpart of such movement the ice engages the guide 12 and falls free of the mold and into tray 6. During upward movement of piston 18, spring 24 is gradually compressed to its solid height, which limits further upward movement of the piston.

When the fluid pressure is-relieved from beneath the pistons, spring 24, acting on flange 20, and thereby on flange 19, retracts the pistons to their initial positions illustrated in Figure 3. Y

Certainfeatures of the piston operation should be emphasized. For one thing, the size of the large piston 17 makes it possible to develop large forces for breaking the ice mass loose from the mold cavity. This is of basic importance since the ice may be tightly adhered to the surfaces of the cavity. The compelling forces that are available through use of the large piston make it unnecessary to apply heat to the mold cavities to free the ice as is required in other types of automatic ice makers; Secondly, by limiting the upward travel of the large piston after the ice is broken loose from the mold, working fluid is conserved, and it is merely necessary to pump a relative small quantity into passage 37 to extend piston 18 for fully ejecting the ice. Of course, relatively smaller forces are available because of the smaller area of piston 18, but these forces are ample for ejecting the relatively light mass of ice. Thus, in summary, the piston assembly executes the necessary movement and is designed to generate large forces forbreaking the ice loose and small forces for ejecting the ice, all with eificient use of the actuating fluid.

Control system The control system does not constitute any part of the present invention and hence will be briefly described. A more detailed explanation of a system suitable for use with the present invention may be found in 'my United States Letters Patent12,7 70,102 which isssued on November 13, 1956, entitled Automatic Ice Maker.

In preface to the description of the over-all operation of the control system, attention is called'to incoming water line 13 shown in Figure 2. It will be noted that the water line delivers water to the first moldcavity, after which the water flows through successive channels 41 tothe' other mold cavities, each mold cavitybeing completely filled before water flows into the-next cavity. In this way, the cavities'are filled sequentially and, after all of them are filled, the flow of water throughline '13 is cut off.

- Thermostat 14 is an important component of the c on trol system since itsenses that the water'within its associated mold cavity is frozen and that the ice is ready fol-harvesting. As illustrated in Figure 2, thermostat 14 may be conveniently supported a'pivoted arm 42 rectly above one of the moldcavities.- When the arm is in its. lowermost position, the lower end of the thermostat projects into. the water content of the mold cavity so that it directly senses the water temperature. At the time the ice is; ejected, the arm is eammed upwardas the ice emerges from its associated mold cavity,- Duringthis movement, the arm engages a horizontal projection 43 of detector arm 8 which is pivotally secured to the mold 10. The detector arm is first li-ftedand then lowered by arm 42 to assure that it comes to rest substantially on the top of the ice supply within tray 6. After ejection of the ice, the arm resumes a normal horizontal position and the detector arm is dropped to a position resting on the ice supply. As will beexplained later, the inclination of the detector arm indicates that a'suitable supplyof -ice has beencollected and is instrumental in terminating operation of the apparatus until ice is removed; from the tray and further operation of th ice maker' is required.

Although use of the pivoted arm 42 as a support for thermostat 14 is convenient, it is not necessary and it should be-understood that the thermostat could be directly engagedwit-h the mold 10 closely adjacent to one of the mold cavities. Heat transfer from water within the.

cavity would be sufficiently rapid to assure that the thermostat correctly senses temperature conditions prevailing therein. In such case arm 42-rnay be retained, nevertheless, for imparting movement to the detector 8 through projection 43.

Briefly, the control system includes a motor driven timer 44, a motor driven pump 45, and a solenoid oper-. ated two-position valve 46'. This valve has a pistonsupply position in which it'permits the passage of fluid to the passage 37 beneath the ice-ejecting pistons, and a fluid-return position in whichit permitsthe return of fluid to the reservoir 51, In addition, a solenoid valve 47 for controlling admission of water to the. mold cavities and a water pressure. regulator 48 areprovided. Also pro vided are a pressure switch 49 and. an electrical interlock 50, all of which elements are illustrated in Figured.

Harvesting ofice is initiated when thermostat 14.detects atemperature of 25 F. or less, signifying that the water has completely frozen .within the cavities. When the normally-open thermostat closes, the timer 44.is energized, which, in turn energizes pump 45, which withdraws operating fluid from reservoir 51, located in the mold 10. The operating fluid may be a 50% solution of water and glycerine, which has a sufliciently low freezing point to assure satisfactory operation. With the valve 46 in its piston-supply position, operating fluid is withdrawn from the; reservoir and pumped directly beneath the plurality of piston assemblies 15. As has b'eenexplained, this forces the pistons into the mold cavities, breaking the; ice masses loose and ejecting them into tray 6.

During this phase of the-operating cycle, heater 52 adjacent thermostat 14 raises the temperature of the thermostat and causes its contacts to open fora purpose to be described shortly. 1 V I When the pistons 17 and 18 are fully extended, pressure rises in the system until the normally open pressure switch 49 closes. This completes an electrical circuit through the solenoid of the two-position valve 46 shifting it to its dashed line position and causing the pump 45 to pump fluid from beneath the piston assemblies back into the reservoir 51',v Since this immediately relieves the pressure in thesystem, electrical interlock Stifisprovided to hold the two-position valve in its energized dashed line position. "Thatis tosay, the interlock. functions as a holding expedient to maintain. the two-position valve in the fluid return position to which it was displaced by the act-ion initiated by the momentary closureof switch 49.

' Continued operation of timer 44 energizes water control valve 47'which admits'water to the mold cavities as' hasabeen explained. Thesolenoid'ot the water valve energized T only for alimited predetermined time period 48pisafunctionof time.

Continued operation of the timer eventually deenergizes the entire system and permits the two-position solenoid valve to return to its original piston-supply position under the influence of gravity. L

Attention is now called to mercury switch 53 associated with detector arm 8. In order for the harvesting cycle to be initiatedbythe closingof thermostat 14, it isnecesary for the detector arm to be in a substantially horizontal position, as will be the case if there is little or no ice in tray 6'; however, if a significant quantity of ice has accumulated the detector arm will be inclined and the mercury switch will remain open, preventing energization of the system. a l 5 Assuming that tray 6 is relatively empty, the detector arm will return to a horizontal; position as soon as the ice has been ejected from the mold. If heater 52. were not provided to open thermostat 14, the ejection cycle would be immediately repeated While water was present in the mold cavities. The heater prevents such premature operation by raising the temperature of the thermostat quickly above 25 F. and opening its electrical contacts.

Attention is called to the fact that a substantial volume of the mold cavities remains even after the piston assemblies are extendedupw-ardly thereinto. For this reason, water can be introduced even before the pistons are fully retracted and for this reason initial energization of the water control valve 47 is not critical.

Mention has been made of spring 24 for retracting the associated pistons. In addition to the spring force, the space beneath the piston assembliesis evacuated by continued operation of the pump" after the two-position solenoid valve is energized into the dashed line position. In this way, complete retraction of the pistons is assured.

It'will be notedthat the system has been described vw'th reference to useof liquid; Attention is called to the fact that the system will also operate it no liquid is present. For instance,"th'e reservoir 51 can be dry and air may be used for extending'the pistons. Thus, the relatively dry air in the reservoir can be pumped beneath the pistons to extend them. Since the air within a refrigerator evaporator is normally extremely dry, use

, of such air will minimize 'condensation problems within the valve and piston assemblies.

By disposing the reservoir directly in the mold, the operating fluid, be it a liquid or dry' air, is maintained at a low temperature and heating of the mold cavities and ice is avoided. This, of course, improves operating efficiency and assures that the iceejected from the cavities will be dry so that fusion of ice stored within tray 6 will not occur. V

After'a harvesting cyclehas been completed, the systemremains inactive until the water supplied to the mold J for freezing ice is relatively short becauseof the excel-. '75:

cavities again freezesand reduces the temperature of thermostat 14 to approximately 25 Fldat'which time the entirecycle is repeated. It will be noted that repetition of the cycle is dependent upon two factors: the temperature of the thermostat must be reduced sufiiciently to closeits electrical contacts; mercury switch 53 must be in a closed position which isestablished when the detector arm 8 is horizontal. accumulated to hold the detector arm in an inclined position, the mercury switch is tilted, breaking its circuit,

and it is not possible to energize the system .toharvest.

additional ice. Only by removal of someof the'accumulated ice from tray 6 and the lowering of the detector arm can harvesting again be effected. p 7

It' is important to note that through use of the present invention an ice maker can be. disposed Qwithina refrigerator without any necessity for passing shafts;tluoughw the'rear wall of the cabinet as required inother, rior art devices. Another feature resides inthe, fact that the'tirne lent heat transfer through the mold to the evaporator.

When sufficient ice has This is due to the direct contact of the water with the surfaces of the mold cavity and tothe fact that the mold is made from highly-conductive material, such as aluminum. i d V From the foregoing description of my invention, it will be appreciated that there is provided a novel form of 1. In an automatic ice maker of the'type defining a: mold cavity in its upper portion, the improvement comprising, in combination: A piston assembly disposed beneath and adjacent the mold cavity defining the bottom surface thereof, said piston assembly comprising an outerpiston slidably retained by the mold and an inner piston concentrically positioned within said outer piston, said outer piston including an integral inwardly extending flange in sliding engagement with said inner piston, a sleeve disposed closely within said outer piston and having an integral inwardly extending flange at its upper end in slidable engagement with said inner piston, a stationary stop pin secured to the mold and projecting through a vertically elongated slot formed in said outer piston and into stationary engagement with said sleeve, said sleeve defining a cylindrical cavity around said inner piston, an outwardly extending flange formed integrally on said inner piston in bearing engagement with the upper face of said integral flange of said outer piston, a compression coil spring within the cylindrical cavity extending between said flange of said sleeve and said flange of said inner piston, seal rings disposed in grooves formed in said sleeve and said outer piston for sealing the relatively sliding surfaces between said outer piston and the mold, and between said sleeve and said inner and outer pistons, and means for supplying fluid pressure beneath said pistons for extending them into the mold cavity, said spring retracting said pistons out of themoldcavity upon release of the fluid pressure.

2. In an automatic ice maker of the type defining a mold cavity in its upper portion, the improvement comprising, in combination: A piston assembly disposed beneath the mold cavity, the upper end of said piston assembly constituting the bottom wall of the mold cavity, said piston assembly comprising an outer large piston and a concentric inner small piston, a stationary sleeve disposed between said pistons and formed to define guiding and sealing surfaces therefor, a compression coil spring surrounding said inner piston and exerting upward' force on said stationary sleeve and downward force on said inner piston, means for transferring downward forces from said inner piston to said outer piston, means for supplying fluid under pressure beneath said pistons, and means for limiting upward movement of said large piston under the influence of fluid pressure.

3. A piston assembly for use in an automatic ice maker comprising an outer piston formed with an inwardly extending flange at its lower end, a, concentric smaller inner piston in guided engagement with the flange of said outer piston, a stationary sleeve disposed between said inner and outer pistons and defining a cylindrical cavity immediately adjacent said inner piston, said sleeve having at its upper end a flange extending into guiding. engagement with said inner piston, an outwardly extending flange on said inner piston normally engaging the making sealing engagement with the adjacent surfaces of said inner and outer pistons. 1 V

- 5. In an automatic ice maker of the type defining a mold cavity in its upper portion to which water is supplied for freezing into a discrete ice mass, the improvement comprising, in combination: A piston assembly disposed immediately beneath the mold cavity, the upper end of said piston assembly comprising at least a portion of the bottom of the mold cavity, said piston assembly comprising an outer piston and a concentric inner pis-- ton, means for supplying fluid under pressure beneath said pistons to extend them into the mold cavity, means for limiting movement of the outer piston after it has broken the ice mass loosefrom the mold cavity, means for limiting extension of the inner piston after it has ejecting the ice from the mold cavity, and means for retracting said pistons after ejection of the ice mass.

7 6. In combination; a mold defining a mold cavity in its upper portion, a piston assembly directly" beneath said mold cavity the upper face of which defines at least in part the bottom 'Wall of the mold cavity, said piston assembly comprising an outer piston and an inner piston,

means for supplying fluid under pressure beneath said limiting relative displacement of the pistons away from a normal positional relationship, means for biasing said pistons into such relationship, said pistons defining a surface of said cavity, and means for supplying fluid under pressure to extend the pistons into the cavity, the last mentioned means applying fluid directly to said pistons.

- 8. In a machine for making ice cubes, said machine being of the type'which includes an evaporator, the com-' bination of: a mold in heat transfer relationship with said evaporator and defining a plurality of mold cavities within which water is frozen into solid masses, each mold cavity being formed with an open upper portion, means for introducing into said cavities and through said upper portions water to be frozen, a plurality of ice ejecting pistons individually mounted for movement in relation to the mold: cavities and retractably positioned to consti-tute a fractional portion of the bottom surface of each mold'cavity, individual concentric means constituting the remaining portion of the bottom surface 'of each mold cavity for water-tightly but slidably sealing the pistons, each piston being formed on one side with a closed surface and on the other side with a surface, isolated from the associated cavity, to which fluid under pressure is directly applied, means for supplying such fluid, and

means for sensinglthe presence of frozen cubes in the cavities and actuating the supply means. 7

9. In an ice cube making machine, the combination in accordance with claim 8 in which each piston has a projected position extending into its associated cavity and a retracted position, individual means for normallyl biasing each' piston into its retracted position, and stop means for limiting the projection of the piston into the associated cavity.

10. In a machine for making ice cubes, said machine: being 'of the type which includes an evaporator, the coinbination of: a'*mold in'lieat transfer relationship with said evaporator anddefining a plurality of mold cavitieswithin which water is frozen into solid masses, each mold cavity being formed with an open upper portion, means dividually mounted for movement in relation to the mold cavities and retractably positioned to constitute a fractional portion of the bottom surface of each mold cavity, individual concentric means constituting the remaining portion of the bottom surface of each mold cavity for References Cited in the file of this patent UNITED STATES PATENTS 1,870,370 Marchaut Aug. 9, 1932 10 Bauer Nov. 29, 1938 Hill May 1, 1945 Rundell May 31, 1949 Cherry et a1. Nov. 22, 1949 Van Vleck Sept. 19, 1950 Watt May 26, 1953 Lees Sept. 25, 1956 Roedter Nov. 13, 1956 Barton July 16, 1957 Chase Oct. 8, 1957 

